First of all Dan, you couldn't have chosen a better place to start. 'The Tal' is one of the great romantic loch-style settings. Plus points for the beginner are: It's shallow (so you know you're never far from the fish), its small-medium size means it's not too daunting for a novice and usually, the fishy areas or hatches can be found in an hour or two. Also, due to the surrounding landscape (a huge steep corridor of mountains!) the wind will almost always blow up or down the length of the lake, affording you long drifts down the middle or parallel to the banks.
Now, don't bother with the drogue unless it blows hard and you are out of your comfort zone and you feel your casting/presentation will benefit from slowing down the pace of the drift. Or, if you have a bad bias or 'crab' to one end of the boat or the other. Deploying the drogue often sorts this, but sometimes you may need to slightly shorten one of the ropes.
Get youselves to the top of the wind, middle of the lake and see how you go. If you achieve a nice straight drift down the middle then fish it out for a while. If sport is 'slow', then move further towards the bank (even the road bank can hold lots of fish close in, just feet from the passing cars) and try to hold a parallel drift.
Main thing is just get comfortable... try to achieve long drifts so that you can get lots of fishing time, and get a feel for the mechanics of it all.
I would strongly recommend you stick to floaters or very slow inters... nowhere for the fish to hide on the Tal. You can touch the bottom with yer rod tip virtually anywhere on the lake, so if yer flies are in the water, they're gonna see 'em.... doesn't always mean they'll take though! Having said that, if you keep it simple, cast a short line in front of the boat (10 to 15 yds max) a couple of pulls to straighten evreything out, them mix up fig8, slow draws, quick pulls for the middle of the retrieve, then lift slowly with a high rod toward the end of the rerieve, then you WILL catch fish. Scratch and stroke the surface.
I would be using a simple 3 fly cast of things like - Silver Invicta, Black Penell, Bibio, Kate MacLaren, Ke-He, Soldier Pamer, Sooty Olive, Fiery Brown, Mallard & Claret, Dabblers etc etc.
If things are slow on top, and you fancy a twiddle with nymphy stuff on an intermediate then try Diawls, Crunchers, PTN's etc.
Let us know how you go mate. I truly wish I was joining you... I've had many a happy day on the Tal and it's high time I returned. Perfect fishing. Good luck.
P.S.
Don't be too surprised if you hook a Sea Trout